Auto merge of rust-lang#96770 - flip1995:fix-trait-type-in-bounds, r=cjgillot

Track if a where bound comes from a impl Trait desugar

With rust-lang#93803 `impl Trait` function arguments get desugared to hidden where bounds. However, Clippy needs to know if a bound was originally a `impl Trait` or an actual bound. This adds a field to the `WhereBoundPredicate` struct to keep track of this information during AST->HIR lowering.

r? `@cjgillot`

cc `@estebank` (as the reviewer of rust-lang#93803)

Author: bors

clippy_lints/src/lib.register_nursery.rs

@@ -29,8 +29,6 @@ store.register_group(true, "clippy::nursery", Some("clippy_nursery"), vec![
     LintId::of(strings::STRING_LIT_AS_BYTES),
     LintId::of(suspicious_operation_groupings::SUSPICIOUS_OPERATION_GROUPINGS),
     LintId::of(trailing_empty_array::TRAILING_EMPTY_ARRAY),
-    LintId::of(trait_bounds::TRAIT_DUPLICATION_IN_BOUNDS),
-    LintId::of(trait_bounds::TYPE_REPETITION_IN_BOUNDS),
     LintId::of(transmute::TRANSMUTE_UNDEFINED_REPR),
     LintId::of(transmute::USELESS_TRANSMUTE),
     LintId::of(use_self::USE_SELF),

clippy_lints/src/lib.register_pedantic.rs

@@ -84,6 +84,8 @@ store.register_group(true, "clippy::pedantic", Some("clippy_pedantic"), vec![
     LintId::of(semicolon_if_nothing_returned::SEMICOLON_IF_NOTHING_RETURNED),
     LintId::of(stable_sort_primitive::STABLE_SORT_PRIMITIVE),
     LintId::of(strings::STRING_ADD_ASSIGN),
+    LintId::of(trait_bounds::TRAIT_DUPLICATION_IN_BOUNDS),
+    LintId::of(trait_bounds::TYPE_REPETITION_IN_BOUNDS),
     LintId::of(transmute::TRANSMUTE_PTR_TO_PTR),
     LintId::of(types::LINKEDLIST),
     LintId::of(types::OPTION_OPTION),

clippy_lints/src/lifetimes.rs

@@ -9,8 +9,8 @@ use rustc_hir::intravisit::{
 use rustc_hir::FnRetTy::Return;
 use rustc_hir::{
     BareFnTy, BodyId, FnDecl, GenericArg, GenericBound, GenericParam, GenericParamKind, Generics, Impl, ImplItem,
-    ImplItemKind, Item, ItemKind, LangItem, Lifetime, LifetimeName, ParamName, PolyTraitRef, TraitBoundModifier,
-    TraitFn, TraitItem, TraitItemKind, Ty, TyKind, WherePredicate,
+    ImplItemKind, Item, ItemKind, LangItem, Lifetime, LifetimeName, ParamName, PolyTraitRef, PredicateOrigin,
+    TraitBoundModifier, TraitFn, TraitItem, TraitItemKind, Ty, TyKind, WherePredicate,
 };
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::hir::nested_filter as middle_nested_filter;
@@ -145,7 +145,7 @@ fn check_fn_inner<'tcx>(
         .filter(|param| matches!(param.kind, GenericParamKind::Type { .. }));
     for typ in types {
         for pred in generics.bounds_for_param(cx.tcx.hir().local_def_id(typ.hir_id)) {
-            if pred.in_where_clause {
+            if pred.origin == PredicateOrigin::WhereClause {
                 // has_where_lifetimes checked that this predicate contains no lifetime.
                 continue;
             }

clippy_lints/src/trait_bounds.rs

@@ -8,7 +8,8 @@ use rustc_data_structures::unhash::UnhashMap;
 use rustc_errors::Applicability;
 use rustc_hir::def::Res;
 use rustc_hir::{
-    GenericBound, Generics, Item, ItemKind, Node, Path, PathSegment, QPath, TraitItem, Ty, TyKind, WherePredicate,
+    GenericBound, Generics, Item, ItemKind, Node, Path, PathSegment, PredicateOrigin, QPath, TraitItem, Ty, TyKind,
+    WherePredicate,
 };
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_tool_lint, impl_lint_pass};
@@ -35,7 +36,7 @@ declare_clippy_lint! {
     /// ```
     #[clippy::version = "1.38.0"]
     pub TYPE_REPETITION_IN_BOUNDS,
-    nursery,
+    pedantic,
     "Types are repeated unnecessary in trait bounds use `+` instead of using `T: _, T: _`"
 }
 
@@ -65,7 +66,7 @@ declare_clippy_lint! {
     /// ```
     #[clippy::version = "1.47.0"]
     pub TRAIT_DUPLICATION_IN_BOUNDS,
-    nursery,
+    pedantic,
     "Check if the same trait bounds are specified twice during a function declaration"
 }
 
@@ -95,6 +96,7 @@ impl<'tcx> LateLintPass<'tcx> for TraitBounds {
         for predicate in item.generics.predicates {
             if_chain! {
                 if let WherePredicate::BoundPredicate(ref bound_predicate) = predicate;
+                if bound_predicate.origin != PredicateOrigin::ImplTrait;
                 if !bound_predicate.span.from_expansion();
                 if let TyKind::Path(QPath::Resolved(_, Path { segments, .. })) = bound_predicate.bounded_ty.kind;
                 if let Some(PathSegment {
@@ -168,6 +170,7 @@ impl TraitBounds {
         for bound in gen.predicates {
             if_chain! {
                 if let WherePredicate::BoundPredicate(ref p) = bound;
+                if p.origin != PredicateOrigin::ImplTrait;
                 if p.bounds.len() as u64 <= self.max_trait_bounds;
                 if !p.span.from_expansion();
                 if let Some(ref v) = map.insert(
@@ -223,6 +226,7 @@ fn check_trait_bound_duplication(cx: &LateContext<'_>, gen: &'_ Generics<'_>) {
     for predicate in gen.predicates {
         if_chain! {
             if let WherePredicate::BoundPredicate(ref bound_predicate) = predicate;
+            if bound_predicate.origin != PredicateOrigin::ImplTrait;
             if !bound_predicate.span.from_expansion();
             if let TyKind::Path(QPath::Resolved(_, Path { segments, .. })) = bound_predicate.bounded_ty.kind;
             if let Some(segment) = segments.first();

tests/ui/trait_duplication_in_bounds.stderr

@@ -67,13 +67,5 @@ LL |         Self: Iterator<Item = Foo>,
    |
    = help: consider removing this trait bound
 
-error: this trait bound is already specified in the where clause
-  --> $DIR/trait_duplication_in_bounds.rs:99:23
-   |
-LL | fn impl_trait(_: impl AsRef<str>, _: impl AsRef<str>) {}
-   |                       ^^^^^^^^^^
-   |
-   = help: consider removing this trait bound
-
-error: aborting due to 9 previous errors
+error: aborting due to 8 previous errors
 

tests/ui/type_repetition_in_bounds.stderr

@@ -19,13 +19,5 @@ LL |     Self: Copy + Default + Ord,
    |
    = help: consider combining the bounds: `Self: Clone + Copy + Default + Ord`
 
-error: this type has already been used as a bound predicate
-  --> $DIR/type_repetition_in_bounds.rs:83:43
-   |
-LL | fn impl_trait(_: impl AsRef<str>, _: impl AsRef<str>) {}
-   |                                           ^^^^^^^^^^
-   |
-   = help: consider combining the bounds: `impl AsRef<str>: AsRef<str> + AsRef<str>`
-
-error: aborting due to 3 previous errors
+error: aborting due to 2 previous errors